linux-kernel - KMSAN: uninit-value in crc32_le

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Message-ID: <000000000000694ba505ba42aa9b@google.com>
Date:   Mon, 01 Feb 2021 01:06:13 -0800
From:   syzbot <syzbot+ce18ece82e1fede33bf7@...kaller.appspotmail.com>
To:     glider@...gle.com, konishi.ryusuke@...il.com,
        linux-kernel@...r.kernel.org, linux-nilfs@...r.kernel.org,
        syzkaller-bugs@...glegroups.com
Subject: KMSAN: uninit-value in crc32_le_base (2)

Hello,

syzbot found the following issue on:

HEAD commit:    73d62e81 kmsan: random: prevent boot-time reports in _mix_..
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=120020acd00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=31d3b433c9628854
dashboard link: https://syzkaller.appspot.com/bug?extid=ce18ece82e1fede33bf7
compiler:       clang version 11.0.1
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ce18ece82e1fede33bf7@...kaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in crc32_body lib/crc32.c:110 [inline]
BUG: KMSAN: uninit-value in crc32_le_generic lib/crc32.c:179 [inline]
BUG: KMSAN: uninit-value in crc32_le_base+0x558/0xe70 lib/crc32.c:197
CPU: 1 PID: 11631 Comm: segctord Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118
 __msan_warning+0x5f/0xa0 mm/kmsan/kmsan_instr.c:197
 crc32_body lib/crc32.c:110 [inline]
 crc32_le_generic lib/crc32.c:179 [inline]
 crc32_le_base+0x558/0xe70 lib/crc32.c:197
 nilfs_segbuf_fill_in_segsum_crc fs/nilfs2/segbuf.c:182 [inline]
 nilfs_add_checksums_on_logs+0x388/0xde0 fs/nilfs2/segbuf.c:320
 nilfs_segctor_do_construct+0x7dd6/0xbf20 fs/nilfs2/segment.c:2072
 nilfs_segctor_construct+0x302/0x1040 fs/nilfs2/segment.c:2377
 nilfs_segctor_thread_construct+0xd6/0x840 fs/nilfs2/segment.c:2485
 nilfs_segctor_thread+0xf35/0x13c0 fs/nilfs2/segment.c:2568
 kthread+0x51c/0x560 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline]
 kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:289
 kmsan_memcpy_memmove_metadata+0x25e/0x2d0 mm/kmsan/kmsan.c:226
 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:246
 __msan_memcpy+0x46/0x60 mm/kmsan/kmsan_instr.c:110
 nilfs_write_dat_node_binfo+0x17a/0x370 fs/nilfs2/segment.c:663
 nilfs_segctor_update_payload_blocknr fs/nilfs2/segment.c:1602 [inline]
 nilfs_segctor_assign fs/nilfs2/segment.c:1625 [inline]
 nilfs_segctor_do_construct+0x4b00/0xbf20 fs/nilfs2/segment.c:2052
 nilfs_segctor_construct+0x302/0x1040 fs/nilfs2/segment.c:2377
 nilfs_segctor_thread_construct+0xd6/0x840 fs/nilfs2/segment.c:2485
 nilfs_segctor_thread+0xf35/0x13c0 fs/nilfs2/segment.c:2568
 kthread+0x51c/0x560 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Local variable ----binfo.i.i@...fs_segctor_do_construct created at:
 nilfs_segctor_update_payload_blocknr fs/nilfs2/segment.c:1558 [inline]
 nilfs_segctor_assign fs/nilfs2/segment.c:1625 [inline]
 nilfs_segctor_do_construct+0x3deb/0xbf20 fs/nilfs2/segment.c:2052
 nilfs_segctor_update_payload_blocknr fs/nilfs2/segment.c:1558 [inline]
 nilfs_segctor_assign fs/nilfs2/segment.c:1625 [inline]
 nilfs_segctor_do_construct+0x3deb/0xbf20 fs/nilfs2/segment.c:2052
=====================================================


---
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